28,140 research outputs found
Simulation and Control of a Pneumatic Muscle Actuator for a Rehabilitation Robot
No full textThe perfomance of a pneumatic muscle actuator, invented by Jim Hennequin and used in a prototype wheelchair-mounted robot ann designed by the first author is reported. Experimental measurements were made of the output torque versus rotary motion and internal pressure. The torque available for a muscle of size 60 mm width by 90 mm length ranges from 1 to 15 Nm. The rotary stiffness of this muscle is 0.081 Nm/deg. A simulation model of the dynamic behaviour of the muscle attached to the robot arm using one-dimensional flow theory was written in ACSL (Advanced Continuous Simulation Language). The resultant simulation gives good agreement to within ± 5% of the experimental values. Control using proportional and a PID controller is shown to be effective
The 'Flexator' as a robotic actuator
No full textDescribes a research project at Middlesex Polytechnic which has been investigating the static and dynamic performance characteristics of a new low-cost pneumatic actuator, invented by Jim Hennequin of Airmuscle Ltd., for use in an electric wheelchair mounted robotic ar
Development of active directional antennae for use in small UAVs
No full textFive different light-weight, medium and high gain directional antennas have been developed, which can be operated together with a gimbals system on the UAV or an antenna tracker system on the ground or with both to extend the range of communication and improve the quality of video signals. The antennas are based on PCB to reduce the mass. There are two types of antennas developed for different transmission frequency: Patch Antenna and Yagi-Uda Antenna. The gimbals system are under developing, which will be based on Arduino Micro Development Board, also quite light, and the board will drive a pan and tilt structure constructed with two small but powerful servos to ensure the antenna to point at the ground station
An optimization study of Coandã wall jet phenomena
No full textThis paper presents a study of the Coandã curve body that specifically used for a Coandã Unmanned Aerial Vehicle. A numerical study over various two-dimensional curve functions is performed using ANSYS Fluent. The Coandã jet blowing conditions are set according to the actual impeller dimension previously used in the actual prototype by Bob Collins
Measurements and simulation of a pneumatic muscle actuator for a rehabilitation robot
No full textThe performance of a pneumatic muscle actuator, invented by Jim Hennequin and used in a prototype wheelchair-mounted robot arm designed by the first author is reported. Experimental measurements were made of the output torque versus rotary motion and internal pressure. The torque available for a muscle of size 60 mm width by 90 mm length ranges from 1 to 15 Nm. The rotary stiffness of this muscle is 0.081 Nm/deg. A theory based on thermodynamic principles indicates that the efficiency of the pneumatic muscle actuator reaches a maximum of 67%. A simulation model of the dynamic behaviour of the muscle attached to the robot arm using one-dimensional flow theory was written in ACSL (Advanced Continuous Simulation Language). The resultant simulation gives good agreement to within ± 5% of the experimental value
Empirical measurements of small unmanned aerial vehicle co-axial rotor systems
No full textSmall unmanned aerial vehicles (SUAV) are beginning to dominate the area of intelligence, surveillance, target acquisition and reconnaissance (ISTAR) in forward operating battlefield scenarios. Of particular interest are vertical take-off and landing (VTOL) variants. Within this category co-axial rotor designs have been adopted due to their inherent advantages of size and power to weight ratio. The inter-rotor spacing attribute of a co-axial rotor system appears to offer insight into the optimum design characteristic. The H/D ratio has been cited as a significant factor in many research papers, but to date has lacked an empirical value or an optimal dimensionless condition. In this paper the H/D ratio of a SUAV has been explored thoroughly, reviewing the performance of these systems at incremental stages, the findings from this study have shown that a range of H/D ratios in the region of (0.41-0.65) is advantageous in the performance of SUAV systems. This finding lends itself to the theory of inter-rotor spacing as a non-dimensionally similar figure, which cannot be applied across a spectrum of systems; this could be attributed to the viscous losses of flight at low Reynolds Numbers (< 50,000
Development of a reconfigurable protective system for multi-rotor UAS
No full textThe purpose of this study is to illustrate how the design and deployment of a minimal protective system for multi-rotorcraft can cater for changes in legislation and provide for greater use both in and outdoors. A methodology is presented to evaluate the design and development of a system which protects both single axial and co-axial rotorcraft. The key emphasis of the development presented is the scenario in which the multi-rotorcraft can fly with increased speed including the capability of flying through windows and doors without the fear of system failure due to rotor disruption. Discussed as well is the degree of autonomy the reconfigurable system should feature as well as the effects of drag and added component mass to the performance of the system
Optimizing performance variables for small unmanned aerial vehicle co-axial rotor systems
No full textThe aim of this project was to design and build a test-rig that is capable of analyzing small unmanned aerial vehicles (SUAV) co-axial rotor systems. The intention of the test-rig development was to highlight important aeromechanical components and variables that dictate the co-axial units flight performance, with the intention of optimizing the propulsion systems for use on HALO® a co-axial SUAV designed by the Autonomous Systems Lab at Middlesex University. The major contributions of this paper are: an optimum COTS co-axial configuration with regards to motor and propeller variations, a thorough review and validation of co-axial rotor systems inter-rotor spacing which in turn identified an optimum H/D ratio region of between (0.41–0.65
The Olasky Interview: Karen Swallow Prior on abolitionist Hannah More
No full textKaren Swallow Prior, a professor of English at Liberty University, is the author of Fierce Convictions: The Extraordinary Life of Hannah More -- Poet, Reformer, Abolitionist (Thomas Nelson, 2014)
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